The invention described herein is a modification and improvement of Australian Patent No. 741667 in the name of the present applicant. The AU741667 patent specification in its entirety is incorporated by reference herein.
A problem of the invention disclosed in AU741667 is that even though the corners and side wall surfaces are movable and settable into position it is possible for them to be misaligned during the moulding process. Where the surfaces interface is the region that is most susceptible to relative movement primarily because of the pressure of the settable material (typically standard or fibre reinforced concrete) along the length of those interfaces but becoming greater at the bottom of the mould. Any misalignment at the interface of the movable parts of the mould will result in there being a surface imperfection in the formed building module. Such imperfections are more likely to occur in association with the internal movable mould panels and thus be noticeable on the inside of the building module. A less than 1 mm misalignment is enough to make the imperfection noticeable.
If the imperfection is a ridge it will be readily apparent on the inside surface of the formed building module and it will not be disguised by painting over it. It needs to be smoothed out and that process is a labour intensive and ultimately expensive process, which also unnecessarily increases the time to manufacture each building module. As there are eight such interfaces (two per corner) there are potentially eight ridges to smooth out per building module.